1. Field of the invention
The invention relates to an optical device with at least one lens and at least one swiveling observation tube.
Such optical devices are, for instance, microscopes and particularly surgical microscopes with two imaging channels for stereoscopic viewing.
2. Description of the Related Art
Optical devices comprising one or two swiveling observation tubes are known from quite a number of prior art references. Just by way of example reference is made to the documents quoted below which, by the way, explicit reference is made to with respect to the explanation of all details or applications which are not mentioned here separately:
German Patent DE 1 098 233, German laid-open Patent Application DE-OS 25 02 209, German Patent DE 26 54 778 C2, German Patent DE 31 05 018 A1, German Patent DE 31 17 254 C2, German Patent DE 33 05 650 A1, German Patent DE 37 18 843 A1, German Utility Model DE-GBM 79 31 427, European Patent EP 0 627 642 A1 and British Patent GB 637 198.
In the device known from the German Patent DE 31 17 254 C2 the observation tube can be swiveled about an axis. A rotatable mirror is disposed with the same axis as the rotational axis of the observation tube, onto which mirror the light beam coming from the lens is deflected by a first mirror fixedly arranged in the base section.
The optical device known from the German Patent DE 31 17 254 C2, which comprises a swiveling observation tube, hence presents disadvantages with respect to both the variability of the viewing direction and the overall length and aperture of the optical system.
The same applies to the optical systems or devices known from the other prior art documents.